Controlling means



Nv. 5, 1929. L. w. EGGLESTON coNTRoLLlNG MEANS 3 Sheets-sheet 1 FiledJune 4, 1923 l rf. ...TE

.4 A TTORNE Y.

Nov. 5, 1929. L. w. EGGLESTQN CONTROLLING MEANS Filed June 4, 1923 5Sheets-Sheet 2 INVENTOR.

Nov. 5, 1929. 1 w. EGGLESTON CONTROLLING MEANS Filed June 4, 1.923 3Sheets-Sheet 3 y fa,

I N VEN TOR.

Patented Nov. 5, 1929 UNITED srnrla-sv LEWIS W. EGGLESTON, OF BUFFALO,NEW YORK, ASSIGNOR T0 AMERICAN RADIATOR COMPANY, OF NEW YORK, N. Y., A.CORPORATION OF NEW JERSEY CONTROLLING MEANS Application filed .Tune 4,i923. Serial No. 643,146.

My invention relates broadly and generally to new and usefulimprovements in controlling means, and While it is capable of embodimentin constructions applicable to the control of various elements andmechanisms, it particularly contemplates the provision of simple andeflicient electric circuit-control ling means adapted to be actuated orset in operation by means responsive to a character istic of a gas orliquid, that is, means which may be responsive to hygroscopic,thermostatic, or pressure conditions.

The invention consists in the improvements to be more fully describedhereinafter,`

and the novelty. of which will be particularly pointed out anddistinctly claimed. I have fully and clearly illustrated the inventionin the accompanying drawings to be taken as a part ot' thisspecification, and wherein- Figure 1 is a sectional View on the line 1-1of Fig. 2, the section being taken through an enclosing casing, andillustrating in front elevation a preferred embodiment of the invention;

Fig. 2 is a vertical central tion through Fig. 1;

Fig. 3 is a view similar to Fig. 1,but showingcertain parts broken awayand others omitted in order to show clearly the position of certainelements during the operation of the device;

Fig. t is an edge view'of a motion-transmitting member, constituting oneof the elements of the embodiment shown in Figs. 1, 2 and 3; p

Fig. 5 is a detail view in front elevation of a supporting frame orbracket;

Fig. 6 is a plan view of the supporting frame or bracket shown in Fig.5;

Fig. 7 is 4a view in rear elevation of a rocking member constituting oneof the elements of the structure shown in Figs. 1, 2 and 3;

F 8 is a view similar't the upper part of Fig. 1, showing certainniodifications, the same being taken on` the line 8 8 of Fig. 9;

Fig. 9 is a vertical central section through Fig. 8;

Fig. 10 is a sectional view corresponding longitudinal see- 'to that`shown in Fig. 2, showing another embodiment of the invention;

Fig. 11 is a longitudinal sectional view on the same line as that ofFigs. 2 and 10, showing a still further embodiment, and

Fig. 12 is a detail sectional view showing a modified constructionadapted to be operated by the pressure exerted by a liquid or gas. i

Referring to the drawings by characters of. reference, 1 designates aback-plate, preferably of insulating material, upon which is mounted asupporting plate 2 spaced from the back-plate to form a space or chamber3, for a purpose to be presently described, and having a marginalstepped iiange 4 having a marginal bead 5 to set over and receive themarginal edge of the said plate 1. The plate 2 is secured to the plate 1by suitable screws 2a, extending through openings in the plate 2 andthreaded into the plate 1. Mounted on the rear of the plate 1 is acasing 6 secured to the said plate in any suitable manner, and having anopening 7 through which circuit wires or leads may extend.

The struct-ure just described constitutes a suitable support for theparts to be hereinyafter described, and it will be understood that myinvention is not limited thereto.

Supported on the front and lower portion of the plate 2 is a rigidbracket-plate 8,

preferably arranged in a vertical plane parallel to the plane of plate2, and provided.

on its vertical side edges with rearwardly extending ears 9 which passthrough open- .ings 10 in the front plate, and are clamped against thewalls of said openings to secure the bracket rigidly in place so thatthe latter is held closely against the said plate 2, as'

shown clearly in Figs. 1, 3 and 5 of the drawings. |The bracket-plate 8is provided at its lower end with a forwardly extending horizontal armor platform 11, provided with 'a forwardly extending slot or recess 12,for a purpose to be presently described. At its upper portion,andpreferably integral with one of its side edges, the said plate 8 isprovided with affo-rwardly extending arm 13,

preferably arranged in a plane at right angles to the plane of the plate8, and provided at its forward portion with a lug or projection 14projecting at right angles to the said arm 13 and overlying and parallelto the plate 8 (see Figs. 1, 2, 3, 5 and 6). The projection 14 isconstructed to provide a suitable fulcrum for a motion-transmittingmember, preferably in the form of a lever, to be presently described,this provision being afforded by forming the lower edge of said arm witha lf-shaped recess 15 extending inwardly and upwardly from said edge,and the .apex 15 of which recess constitutes the fulcrum for said memberor lever, as will be presently described.

As heretofore stated, the switch is adapted to be operated by suitablepower means, for exemple, an eXtensible-retractible element, which maybe responsive to thermostatic, pressure or hygroscopicl conditions,but'for the purposes of this application l will describe the same in apreferred form as being operated by a thermostatically responsiveelement in the form of an eXpansible-collapsible corrugated vessel,preferably consisting of a circumferentially corrugated metal cylinder.

nilhis power element, which, as stated, may be thermostaticallycontrolled or operated, is supported upon the bracket-arm 11, heretoforedescribed, and comprises a rigid tube or hollow column 15 having itslower end threaded, as at 17, and projecting through the slot or recess12, heretofore described, said tube being rigidly secured in place by anut 18 threaded onto the lower end of the tube below the arm 11 andclamping the saine on the said arm. At its upper end portion the tube orcolumn 16 is provided with a circumferential collar 19, upon which isseated a head 20 of a vertically arranged metallic cylinder 21, saidhead having a central opening through whichsaid tube extends, thecylinder being secured to the tube riveting down a ortion of the latter,as at 22, upon the upper ace of the head, whereby the latter is clampedrigidly upon the collar 19. rl`he joint between said tube and head atthis point is preferably sealed b soldering, so as to be gas andliquid-tight. The cylindrical wall 21 extends downward from the head fora suitable distance, and is provided at its lower edge portion with anoutwardly extending circumferential flange 23, to which is secured andsealed the lower end 211 of an expansiblc` collapsible element,comprising a cylindrical corrugated wall or vessel 24 to which isimparted longitudinal resiliency by means of the corrugations therein,as will be apparent from the drawings. The upper end portion of theeXpansible-collapsible element extends above the head 20 for a suitabledistance, and is secured and sealed at its edge, as at 25, to aclosure-head 26, provided with a central, preferably circular, pocket orrecess 27. and with a central opening 28 through which the upper end ofthe tube or column 16 projects said opening being large enough to permitthehead to slide freely on said tube. Carried by the head-plate 26 is aplunger, which may take a number of'forms within the spirit and scope ofmy invention, but preferably consists of an inverted cup-shaped cylinder29, the open end of which is inserted in and snugly lits the recess 27,and is sealed therein by solder or other suitable agent, so that aclosed chamber is formed, as shown in Fig. 2. rlhe upper end or head 30of the plunger is provided with a depression or recess 31 constituting aseat, for a purpose to be presently described.

The upper end ofthe tube 16 is internally threaded, as at 32, to receivea headed plug 33, the head of which overlies and projects laterallybeyond the side of the tube 16 to form an annular stop-shoulder 311 withwhich the head 2G cooperates to limit the upward or expansive movementof the corrugated ezrpansiblecollapsible element.

The plug 321 is provided with a central bore 35, by which communicationis established between the bore 16"L of the tube 1G, the interrior ofthe plunger 29, and thiaugh a slight opening or space between the head2G and said tube 1G, with the internal chamber 21a established betweenthe cylindrical member 21 and the surrounding corrugatedeXpansible-collapsible element. it its lower end the column 16 is openand receives, in the case of a thermostatic device, a filling tube 36,through which the interior of the eXpansible-collapsible element may beevacuated, and a suitable volatile liquid placed therein, after whichthe filling tube is sealed by pinching together, or otherwise, as may bedesired. lt will be understood that the volatile substances selectedwill depend upon the use to which the device is to be put; for example,in the case of room control, where the device is intended to respond tothe ordinary fluctuations of temperature present in a living-room, asuitable amount of ethylchloride may be the volatile liquid employed. lfthe device is to be controlled for temperatures other than that existingordinarily in a living-room, other volatiles, or mixtures thereof, maybe employed; for example, for refrigeration purposes'where rerotemperature is to be the controlling factor, methylchloride may beemployed. lf freezing temperature is to be the controlling factor,carbondioxide may be employed. lt is obvious that other volatilesubstances may be selected in accordance with the temperature conditionsdesired to control the device.

lThe expansion or extension of the expansible-eollapsible element justdescribed is employed to transmit motion to improved means for makingand breaking a circuit. rl`his means con'iprises a lever, indicated,generally, at 37, consisting of a' plate provided at its llO Y foredescribed, and on its opposite or rear edge said plate is provided withalug or pintle 40 having a knife-edge il (see dotted lines, Fig. 1) uponits lower edge portion,f

which pintle 40 projects through an opening 42 in the plate 8. whichopening has a V- shaped seat 42a with which the knife-edge 4l cooperatesto provide a knife-edge fulcrum on the rear edge of the lever plate. YIt is to be noted that the fulcrums 15a and 42a are arranged on thesaine horizontal line.A The plate 37 is provided with an integral arm 37a extending at an angle thereto and having its end seated in the recess31, heretofore described, whereby the Alever plate is moved by thethermostatic element when Jthe latter expands. The arm 37 a ispreferably provided by striking the same out of the body of the plate37, as will be clear from F i gs. 1, 2 and 4 of the drawings. The leverplate is arranged to swing in the space between the arm 14 and the mainportion of the plate 8, and by providing the oppositely directedknife-edge fulvcrums, that is, one facing upward and the other downward,the lever when subjected to the force exerted by the thermostaticelement, and a spring to be hereinafter described, is held to itsfulcrums and prevented from rocking out of engagement therewith.

' lhe lever-plate 37 is provided at its upper portion with suitableengaging means, preferably including a rearwardly and upwardlyprojecting arm 44 projecting through an opening in the plate 2 into thespace 3, and carrying an upward projection 45 constituting one of a pairof engaging lugs for engagement with parts to be presently described.The late 37 is provided on one face with a mova le section 46,yieldingly held in engagement with said plate 37 by means of a headedscrew 47 passing through said plates and carrying on one end 'a nut 48,an expansion spring 49 being arranged between the section 46 and thehead of said screw to provide for a resilient or yielding connection,and to permit slight yielding motion of the plate 46 away from the leverplate 37.

The plate or section-46 is provided with side lugs or projections 49abent at right angles to the plane of the plate and seated in notches 49bin the side edges of the lever 37, whereby the plate 46 is held againstturning movement on said lever.- At its upper end the plate 46 isprovided with a rearwardly and upwardly inclined arm 50 having anupwardly directed lug 51, providing with the corresponding portions 44,45, heretofore mentic-ned, a recess 52 to receive an engaging device ona member which will now be described:

On the upper portion ofthe plate 2,..and se- .cured rigidly thereto, isa forwardly extendwhich also extends through an opening 57 in the plate2. Upon the bearing-pin 56 is arranged a rocking member, consisting,preferably, of a horizontal plate 58 having at its rear end a downwardlyprojecting member 59,

'which is provided with a rearwardly extending lug 60 projecting throughan opening in the plate 2 into the space in rear of said plate and whichlug is located in the recess 52 heretofore described, whereby therocking of the lever 37 will serve to rock the member 58 on itsbearing-pin 56. The plate 58 is provided on its forward end with adepending arm 61, upon the front and rear of which may be mounted one ormore U-shaped spring clips 62, the arms of which are adapted to receivea contact-making and breaking element. ln the preferred embodiment thiscontact-making` and breaking element consists of\ an evacuated tube 63,preferably of glass, an/dadapted to contain a fluid contact element,such as mercury, shown at 64. At its opposite end portions the element63 contains pairs of contacts 65, 66, respectively, which, when the tubois rocked in one direction or the other, are adapted to have the mercuryflow into engagement therewith to close a circuit between .the contactsof either pair, as indicated-in Fig. 1 of the drawings, in which thefull lines show the tube in the position in which the mercur is inengagement with the air of Y passes when being rocked.

Provision is made for limiting fthe swinging movement of the element 61so that the lever 37 will be permitted to swing the contact member onlyfar enough to properly immerse the contacts of a pair at one end of thetube 63, and so that the tube will not `be swung so far that the mercuryorotheur fluid element will uncover the innermost l.contact of a pairand only immerse the outer contact. The stop means may take a number offorms, but, preferably, the plate 58 is made of such width thatthe endedges 58 thereof will contact with the end portions of theY horizontalmember of the bracket 53, thus serving to limit the swinging movement ofthe member 58 in either direction. The flexible connection of the member46 with the lever 37 affords a yielding or resilient connection betweenthe lever and the lug 60, so that the member 46 i lll) 67, to which isconnected one end 68 of a contractile spring 69, the other end of whichis fixed or anchored, as at 70, upon a nut 71, ad- ]ustably threaded onthe end of a screw 72, rotatably mounted in an opening 73 in anadjusting device or handle 74 arranged beneath the casing in engagementwith the flange 4, and movable transversely thereof. |The lower portionof the flange 4 is preferably arcuate, as at 4, and slidably receivesthe device 74, th'.- latter having a projection 74rt extending through aslot 74" in the iange. The screw 72 provides convenient means forregulating the tension of the spring 69. The handle 74 may be providedwith a suitable indicator 75 adapted to cooperate with a scale 76 on theplate 2, Ain order topermit the adjustmentof the spring to cause thethermostatically or pressure operated device to operate at a desirc-dtemperature.

Itis to be noted that the axis of the fulcrum for the lever 37 islocated to one side of the longitudinal axis of movement of the powerelement, and the point of engagement between the lever 37 and thecontact-shifting support 1s at a point either on or slightly to one sideof the longitudinal axisof movement of the power element. 1t is also tobe noted that the connection of the spring with the lever 37 is locatedabove the lever fulcrum, and that the anchorage for the other end ofthespring is so located on the opposite side of the said fulcrum, thatsaid spring at all times exerts its force along a line extending at anacute angl to the lever power element. The pairs of contacts 65, 66, inthe embodiment shown, are connected, respectively, to pairs of circuitleads 77, 7 8, forming part of a circuit orcircuits leading to anysuitable device adapted to be electrically controlled. The leads may besupported and separated by front and rear plates 79, 80, and an inter-:mediate plate 81, of insulating material,

located above the bracket 53. The plates 7 9, 80 are spaced from eachother, and supported loosely on a headed bolt 82 rigidly mounted on theplate 2 above the bracket 53. The plates are held against' rotation by apin 83 fixed at one end on the plate 2, and passing through openings inthe saidv plates 79, 80, 81, whereby the plates are movable lengthwiseof said bolt and pin.y but are held against rotation. VThe plates 79,80, 81 arel provided with openings 84 through which the said leads 77,78'pass, and are held separated from each other, as will be apparentfromFigs. 1 and 2 of the drawings.

It will be understood that my invention is not limited broadly to anyspecific form of contact-maker, or to any speciic construction forsupporting the circuit wires or leads.

The construction and arrangement of 'parts being as above described, theoperation is as follows: It will be understood that the expansible-collapsible element has been evacuated to the desired degreeand charged with a proper Vquantity of a volatile substance necessary tosuit the conditions of use, and to cause the vessel to expand whensubjected to certain temperature conditions. The spring 69 is thenadjusted 'by means of the movable anchorage to offer sutlicientresistance to the expansible-collapsible element to prevent expansionthereof until -a certain temperature is reached, say, for example, 7 2F. By setting the anchorage at the mid-position on the scale, the springwill have sufficient resistance to prevent expansion of the elementuntil a. temperature of 72 is reached, and until this occurs will holdthe parts in the position shown in full lines in Fig. 1, with themercury closing the circuit through the contacts 65. Then lthetempera-ture reaches 72`F. and is slightly exceeded, resulting insufcient pressure being built up in the expansible-collapsible elementto create sutEcient power to overcome the spring resistance, the saidelement expands and acts on the lever 37 to: Vthrow the same toward theleft of Fig. 1.

The movement just described rocks the support 59 to incline thecontact-maker in the opposite direction from that shown in Fig. 1, thatis, to the position shown in Fig. 3, wherebv the mercurv Hows out ofengagement with l. n

contacts 65, breaking the circuit at that point, and into contact withcontacts 66, closing the circuit through the latter. So long as thetemperature remains at or above that for which the spring is set, theparts will be held ln the position shown in Fig. 3, but as soon as thetemperature falls slightly below 7 2o F., the gas in the element 24condenses, and the spring exerts its force to return the parts to theposition shown in full lines in Fig. 1. It will be noted, that due tothe fact that the spring extends at an acute angle to said lever and isanchored at its lower end at a point below the fulcrum 39, and is alwayslocated to one side of said fulcrum, whenever the power element operatesthe lever the longitudinal line of the spring will move closer to thefulcrum, and thereby the angle of force at which the spring acts uponthe lever is reduced or decreased, thereby reducing the resistance ofthe spring to said element. By reducing the leverage of the spring atthe start of the movement, the expansion of the power element takesplace freely -under the internal starting pressure, without regard tothe mechanical resistance of the wall of said element, th at is, theinherent resistance of the thermostatic element, due to its resilience.In other words. when the spring is set to prevent operation Yof thedevice by the power element until a certain temperature is reached, itwill' maintain this position until such temperature causes the volatilein the thermostatic device to be volatilized, whereupon only a slightdegree of power exerted by the power element in excess of the springresistance is necessary to overcome the spring, for the reason that theleverage of the latter relative to the lever 37 being reduced theinstant the bellows starts to expand, the bellows power quicklyovercomes the spring and throws the lever sharply to shift thecontact-making device. In this operation, the spring power or resistanceis not gradually overcome, but is overcome quickly and suddenly, due tothe fact that the swinging of the spring so as to shorten the leverageprevents the spring tension or power building up, and actually reducesit, while the bellows expands.

It will be understood that when the spring is set to cause the device toact to operate at a certain temperature, the spring maintains theexpansible-collapsible element slightly collapsed against its inherentspring or resilient tendency to expand, and that as soon as theoperative temperature causes the expansiblecollapsible element to expandto have sufficient movement to swing the lever 37, the resistance of thespring, because of the change of the angle of leverage, is reduced, andthe natural bellows force tending to expand plus the internal forceexerted by the volatilization of the volatile liquid gives sufficientpower to quickly overcome the spring. By properly proportioning theforce of the spring relative to the force exerted by theexpansible-collapsible element, due to its inherent tendency to expand,the device may be caused to operate with a snap action within a smalldegree of temperature differential. By determining the relation betweenthe spring resistance and the resilient bellows force, the temperaturedifferential to which the device will respond, and the speed with whichthe operating lever will be moved, may be readily ascertained to suitdifferent conditions of use.

When the lever has been actuated by the power element, as abovedescribed, it will beheld in this position so long as conditionsmaintain the power element extended or expanded, but as soon asconditions result in the collapse or contraction of the-power element,the resistance thereof to the spring is relieved, and the spring actssharply and quickly to return the lever with a snap movement to normalposition, and to hold it in thisposition until it is again actuated bythe power element. j

l/Vhen the power element collapses or reftracts, the spring contracts topull the lever 37 to the position shown in Fig. 1, and as soon as thismovement starts, the angle of leverage of the spring on Athe lever isincreased slightly, and acting against .the resistance of the bellowsreturns the lever to initial position with a snap movement. It will beunderstood thaty at all times there is an internal pressure within thebellows exerted by the expanded volatile material, but it is only theincrease or decrease of this pressure relative to a fixed point whichresults in the operations heretofore described. e

In Figs. 8 and 9 I have shown another arrangement of the support for acontact-maker or switch and the connection between the operating leverand said support. VIn this form of the invention, the main portion ofthe lever 37 is provided with a pair of vertical, spaced projections orarms 85, in each of'which is threaded an inwardly directed adjustingscrew 86, between the inner ends of which is received a lug 87 on adownwardly projected arm 59'd carried by a rocking support 58h, which isalso provided with a depending arm 61a having an integral spring clip 88adapted to receive and hold a contactmaking device 63a, similar ingeneral onstruction and operation to the contact-ma er 63 heretoforedescribed, but with the difference that it is provided with but one pairof contacts, as shown at 89. The spring clip is adapted to grip thecontact-maker 63 at its central portion and to be clamped about the sameby means of a clamping screw 90 passing through the members 91 of acrimp formed in said clip, as will be clear from Figs. 8 and 9.' In thisembodiment of the invention, the rocking member 58b turns on a bearingpin 56a mounted in an opening in the lower end of a downwardlyprojecting arm 54a on a bracket arm 53, and an opening in the plate 2.In this form the construction and arrangement of the spring may be, andpreferably is, the same as that heretofore described, and suchdescription need not be' repeated.

In Fig. l0 I have shown another embodiment in whichthe device isthermostatically operated. In this form, the instrument is supported ona bracket arm 92 having a threaded base 93 adapted to be threaded intothe outer end of a collar 94 having a threaded neck 95 to be inserted ata suitable point, subject to the controlling temperature. This collarcarries a thermostaticchamber 96 provided with a flange 97 overlying ashoulder 98 in the collar 94:, and clamped thereon by the lower end ofsaid base 93. The chamber or vessel 96 is sealed at its upper end by asuitable plug 98', and the interior thereof is connected to the bore 16aof the tube 16 by means of a tube99 inserted through the sealing plug98. In this construction, the vessel 96 is located at any point subjectto the controlling temperature, and contains a suitable expansible orvolatile liquid which, upon heating to a given temperature, exerts itspressure either through expansion or volatilization upon theexpansible-collapsible element to operatethe controlling device in themanner heretofore described. In this form the instrument may be employedfor controlling any device associated with a hot temperature of thewater therein.

In the form shown in Fig. 11, the power element for operating theinstrument, as heretofore described, is omitted, and in place thereofsaid instrument is operated by a device subjected to the pressurecharacteristic of a gas or fluid. 'In this construction, the instrumentmay be mounted upon an arm 100 projected vertically from the cover/orcap 101 of a casing 102, having at its lower portion a threaded nipple103 adapted to be inserted in communication with a suitable source ofpressure, for example, -a steam space of a steam boiler. The casing 102contains an eX- pansible-collapsible element consisting of acylindrical, circumferentiallj,Tr corrugated metallic vessel 104 havinga closed lower end or head 105, and the upper open end of which isconnected and sealed, as at 106, to a securing ring or flange 107, theouter edge of which is clamped between a shoulder 108 on the cover orcap 101 and the upper edge of the casing. The eXpansible-collapsiblevessel 104 contains an internal reenforcing plate 109 clamped inposition against the head 105 by rollingportions of the latter aroundthe edge of said plate, as shown at 110, and upon said plate is aprojection 111 slidably arranged within a plunger bar 112 arrangedcentrally of the vessel. The upper -end of the plunger bar has threadedthereto an eX- tension 113 extending slidably through a guidellflfthreaded into the center of the cover, and the upper end of whichprojects through the recess 12 in the ybracket 11, and carries at itsupper end a thrust-rod 115, the lower end of which is Vadapted to restupon the bracket 11', and the upper end of which:

is recessed, as at 116, to receive the lower end of the arm. Thethrust-rod 1-15s adjustably threaded, as at 117, upon the upper end ofthe plunger bar, and is adapted to he secured inadjusted position by aset lscrew -118. p The steam or other pressure element flows .into thecasing around the eX- pansible-collapsible element 104, and-when thepressure reaches the determined point,

the said element is collapsed to thrust the thrust element upward toactuate the instrument, the operation of the latter being the same asheretofore described; y

Ifjdesired, instead of operating lever 37 thermostatically by thepressure of the gas resulting from volatilization'o material within thevessel 25, I may employ said ves sel as a pressure-responsivedevice.This is accomplished by the arrangement shown in Fig. 12, in whichthe'sealed filling tube 36 isremoved, and in place thereof a conduit 36Lis sealed in the borel of the column 16 and is connected with anysuitable source of pressure acting as the controlling or actuatingmedium.

Whatl claim and desire to secure by Letters Patent of the United Statesis 1. In a device of the character described,

controlling means, operating means responsive to a characteristic of agas or fluid, a lever for transmitting motion from said operating meansto said controlling means, a spring acting on the lever throughout themovement ot' the latter to oppose said operate ing means, and means forso supporting said spring that the leverage of the latter relative tosaid lever is automatically reduced when said lever is operated by saidoperating means.

2.. In a device of the character described, controlling means, operatingmeans responsive to a characteristic of a gas or liquid, a lever fortransmitting motion from said operating means to said controlling means,and a spring acting on said lever to oppose said operating meansthroughout the movement of the lever, said spring having one endconnected to the lever and the other end anchored at a point so locatedthat the leverage of the spring relative to the lever is reduced whenthe lever is operated by the said operating means.

3. In a device of the character described, operating means responsive toa characteristic of a gas or liquid and acting in a direction in asubstantially straight line, a lever fulcrumed at a point to one side ofthe line of movement otsaid operating means and transmitting motion fromsaid operating means to said controlling means, and a contractile springacting on said lever to oppose said operating means throughout themovement of the lever, said spring having one end connected to saidlever and the other end anchored at a point on the opposite side of thelever fulcrum and so located that the leverl age of the spring relativeto the lever is varied when the lever moves under influence of theoperating means.

4. In a device of the character described, controlling means, operatingmeans responsive to 'a characteristic of a gas or liquid and acting in adirection in asubstantially straight line, a lever ulcrumed at a pointto one side of the line of movement of said operating means andtransmitting motion from said operating means to said controlling means,and a contractile spring acting on said lever to oppose said operatingmeans throughout the movement of the lever, said spring having one-endconnected to said ,lever and the other end anchored at a point on theopposite side of the lever vfulcrum and so located that the leverage ofthe spring relative to the lever is reduced when the lever swings in onedirection, and increased when the lever swings in the other direction. l

5. In a device of the character described, controlling means, a leverfor operating said controlling means, operating means responsive to acharacteristic of a fluidl or gas for moving said lever in onedirection, and a spring opposing operation ofsaidleverby said operatingmeans, said spring having one end connected to the lever and the otherend anchored at such` point that said spring is located to one side ofsaid lever and exerts its force along aline at an acute angle to thelength of the lever throughout the movement of the latter whereby theleverage of the spring is reduced when the operating means responds to apredetermined condition of the gas or liquid.

6. In a device of the character described, controlling means, a leverfor operating said controlling means, operating means responsive to acharacteristic of a. fluid or gas for moving said lever in onedirection, and a spring opposing operation of said lever by saidoperating means, said spring having one end connected to the lever andthe other end anchored on the opposite side of the lever fulcrum at suchpoint that said spring exerts its force along a line at an acute angleto the length of the lever whereby the leverage of the spring is reducedwhen the operating means responds to a predetermined condition of thegas or liquid.

7. In a device of the character described, y controlling means, a leverfor operating said controlling means, operating means respon. sive to acharacteristic of a fluid or gas for moving said lever in one direction,a spring opposing operation of said lever by said operating means, saidspring having one end connected to the lever and the other end anchoredat such a point that said spring lexerts its force along a line at anacute angle to the length'of the lever, whereby the leverage of thespring is reduced when the operat` ing means responds to a predeterminedcondition of the gas or liquid, and means for .regulating the power ofsaid spring to vary the point at which the operating means actuates saidlever.

8. In a device of the character described, controlling means, a leverfor operating said controlling means, operating means responsive to acharacteristic of a fluid or gas for moving said lever in one direction,a spring opposing operation of said lever by said op' erating mea-ns,said spring having one end O connected to the lever and the other endanchored at such a point that said spring exerts its force along a lineat an acute angle to the length of the lever, whereby the leverage ofthe spring is reduced when the operating means responds to apredetermined condition of the gas or liquid, and adjustable means forvarying the angle at which the -force of the spring is applied to saidlever.

9. In a device of the character described, controlling means, a leverfor operating said controlling means, operating means responsive toacharacteristic of a fluid or gas for moving said lever in one direction,a spring opposing operation of said lever by said operating means, saidspring having one end connected to the lever and the other end anchoredat such a point that said spring exerts its force along a line at anacute angle to the length of the lever, whereby the leverage of thespring 1s reduced when the operating means responds to a predeterminedcondition of the gas or liquid, and means for varying the position ofsaid anchorage to vary theangle at vhich the force vot the spring isapplied to said ever.

10. In a device of the character described, controlling means, a leverJfor operating said controlling means, operating` means responsive to acharacteristic of a uid or gas for moving said lever in one direction, aspring opposing operation of said lever by said operating means, saidspring having one end connected to the lever and the other end anchoredat such a point that said spring exerts its force along a line at anacute angle to the length of the lever, whereby the leverage of thespring is reduced when the operatingmeans responds to a predeterminedcondition of the gas or liquid, and manually adjustable means forvarying the angle at which the force of the spring is applied to saidlever. y ll. In a device of the character described, controlling meansincluding a rocking member, a lever for operating said rocking member,operating means responsive to a characteristie of a gas or fluid andadapted to op! erate said lever, and a spring acting on said lever tooppose said operating means throughout movement of the lever, saidspring having one end connected to the lever and the other end anchoredto a point so located that the leverage of the spring relative to thelever 'is reduced when the lever is operated by said operating means.

12. In a device of the character described, controlling means includinga rocking member, stop means to limit movement of said rocking member, alever for Operating said rocking member, operating means responsive to acharacteristic of a gas or iiuid and adapted to operate said lever, anda spring acting on said lever to oppose said operating means throughoutmovement of the lever, said spring having one end connected to the leverand the other end anchored to a point so located that the leverage ofthe spring relative to the lever is reduced when the lever is operatedby said operating means.

13. In a device of the character described, controlling means includinga rocking inember, stop means to Vlimit movement of said rocking member,operating means responsive to a characteristic of a gas or fluid, alever transmitting motion from said operating means to said rockingmember, a yielding connection between said lever and said rockingmember, anda spring acting on said lever to oppose said operating means,said spring having one end connected to the lever and the other endanchored to a point so located that Aso the leverage of the springrelative to the lever is varied when the lever 1s operated by saidoperating means.

14. In a device of the character described,-

controlling means including a rocking mem'- ber. stop means to limitmovement of said rocking member. operating means responsive toa'charactcristic of a gas or liquid, a leverfor transmitting motion fromsaid operating means to said rocking member, a member yieldinglysupported on said lever, said lever and said member supported thereonhaving spaced engagingidevices adapted to engage said rocking member,and a spring acting'on said lever to oppose said operating means, saidspring having one end connected to the lever and the other end anchoredto a point so located that the leverage of thespring relative to thelever is reduced when the lever is operated by said operating means.

15. In a device of the character described, a rocking member, acontact-making and breaking device supported on said rocking member tobe rocked thereby and comprising a sealed vessel containing contacts anda Huid,

conductor adapted to How into and out of engagement with said contacts,stop means to I limit movement of said rocking member, op-

erating means responsive to a characteristic of a gas or l1qu1d, a leverfor transmittmg Vmotion from said operating means to said rockingmember, a yielding connection between said lever and Said rockingmember, and a spring acting on said lever to oppose said operatingmeans,said spring having one end connected to the lever and the other end anchored to a point so located that the leverage of the springrelative to the lever is varied when the lever is operated by saidoperating means.

16. In a device of the character described, a rocking member, acontact-,making and breaking device supported on said rocking member tobe rocked thereby and comprisin a sealed vessel containing contacts anda flui conductor adapted to flow into and out of engagement with saidcontacts, stop means to limit movement of said rocking member, operatingmeans responsive to a characteristic of a gas or liquid, a lever fortransmitting motion from said operating means to said rocking member,and a spring acting on said lever to oppose said operating means, saidspring having one-end connected to the lever and the other end anchoredto a point so located that said spring is at one side of said leverthroughout movement of said lever and the leverage of. the springrelative to the lever is varied when the lever is operated by saidoperating means.

17. In a device of the character described, a rocking member, acontact-making and breaking device supported on said rocking member tobe rocked thereby andv comprising a sealed vessel containing contactsand a fluid conductor adapted to flow into and out of engagement withsaid contacts, stop means to limit movement of said rocking member,thermostatically responsive operating means, a lever for transmittingmotion from said operating means to said rocking member, a

rocking member, a contact-making and breakingdevice supported on saidrocking member to be rocked thereby and comprising a sealed vesselcontaining contacts and a fluid conductor adapted to iow into and out ofengagement with said contacts, stop means to limit the movement of saidrocking member, an expansible-collapsible vessel responsive to acharacteristic of a gas or liquid, a lever for transmitting motion fromsaid expansiblecollapsible vessel to said rocking member, a yieldingconnection between said lever and said rocking member, and a springacting 011 said lever to oppose said eXpansible-collapsible vessel, saidspring having one end connected to the lever and the other anchored Atoa point so located that the leverage of the spring relative to the leveris varied when the lever is operated by said operating means.

19. In a device of the character described,

controlling means, a lever for operating said controlling means, aneXpansible-collapsible vessel responsive to a characteristic of a Huidor gas for moving said lever in one direction, and a spring opposingmovement of said lever by said operating means throughout movement ofsaid lever, said spring having one end connected to the lever and theother end anchored on the opposite side of the lever ulcrum at suchpoint thatsaid spring exerts its force along a line at an acute angle tothe length of the lever, whereby the leverage of the spring is variedwhen the eXpansible-collapsible vessel responds to a predeterminedcondition of the gas or liquid.

20. In a device of the character described, controlling means, a leverfor operating said controlling means, an eXpansible-collapsible vesselresponsive to a characteristic of la fluid or gas for moving said leverin onev direction, a spring opposing movement of said lever by saidoperating means, said spring having one end connected to the leverandthe other end anchored on the opposite side of the lever .fulcrum atsuch point that said spring exerts regulating the langle of leverage ofsaid spring on said lever.

2l. In a device of the character described, a rocking member, acontact-making and breaking device supported on said Arocking member tobe rocked thereby and comprising a sea-led vessel containing contactsand a fluid conductor adapted to flow into and out of engagement withsaid contacts, an expansible-collapsible vessel responsive to acharacteristic of a gas or liquid, a lever :tor transmitting motion fromsaid expansible-collapsible vessel to said rocking member, and a spring'opposing operation of said lever by said expansible-collapsible element,said spring having one end connected to the lever and the other endanchored on the opposite side of the lever ulcrum at such pointthat saidspring exerts its force along a line at an acute angle to the length ofthe lever.

22. In a device of the character described, a rocking member, acontact-making and breaking device supported on said rocking member o tobe rocked thereby and comprising a sealed vessel containing contacts anda fluid conductor adapted to low into and out of engagement with saidcontacts, an expansible-collaps'ible vessel responsive to acharacteristic of a gas or liquid, a lever for transmitting motion fromsaid expansible-collapsible vessel to said rocking member, a springopposing operation of said lever by said expansiblecollapsible element,said spring having one end connected to the lever and the other endanchored on the opposite side of the lever fulcrum at such point thatsaid spring exerts its force along a line at an acute angle to thevlength of the lever, and manually operable means for setting theposition ot the spring to vary the angle at which the force of thespring is applied to said lever.

23. ln a device of the character described, a rocking member, acontact-making and breaking device supported on 'said rocking member tobe rocked thereby and comprising a sealed vessel containing contacts anda lluid conductor adapted to iiow into and out of engagement with saidcontacts, a thermosensitive expansible-collapsible vessel responsive toa characteristic o t a gas or liquid, a lever for transmitting motionfrom said expansiblecollapsible vessel to said rocking member, and aspring opposing operation of said lever by said expansible-collapsibleelement, said spring having one end connected to the lever and the otherend anchored on the opposite side of the lever fulcrum at such pointthat said spring exerts its force along a line at an acute angle to thelength of the lever.

24e. In a device of the character described, a support, acircuit-controlling devicemounted for rocking movement on the support, abracket on the support beneath said device, an expansible-collapsiblecorrugated vessel on said bracket and movable toward and away from saiddevice, a lever ulcrumed on said support to one side of the axial lineof movement of said vessel, a part on said lever and engaged by saidvessel, the upper end ofsaid lever engaging said device, and a springopposing t-he expansive movement o said vessel and having one endconnected to the upper portion ot said lever and its other end anchoredat a point below the ulcrum of said lever, said spring exerting itsforce along-a line at an acute angle to the length of said lever.

25. In a device of the character described, a support, acircuit-controlling device mounted for rocking movement o n the support,a bracket on the support beneath said device, an expansible-collapsiblecorrugated vessel on said bracket and movable toward and away from saiddevice, alever ulcrumed on said support to one side of the axial line ofmovement of said vessel, a part on said lever and engaged by saidvessel, the upper end of said lever having means for yieldingly engaging4 said device, and a spring opposing the expansive movement ot` saidvessel and having one end connected to the upper portion of said leverand its other end anchored at a point below the ulcrum of said lever,said spring exerting its Jrorce alongra line at an acute angle tothelength of said lever.

26. In a device of the character described, a support, acircuit-controlling device mounted for rocking movement on the support,a bracket on the support beneath said device,

an eXpansible-collapsible corrugated vessely on said bracket and'movabletoward and away from said device, a lever ulcrurned -on said support toone side of the axial line of movement ot said vessel, a part on saidlever and engaged by said vessel, the upper end of said lever engagingsaid device, a spring opposing theexpansive movement of said vessel andhaving one end connected to the upper portion ot said lever and itsother end anchored at a point below the ulcrum of said lever, saidspring exerting its force along a line at an acute angle to the lengthof said lever, and means for regulating the angle of said springrelative to said lever.

27'. ln a device of the character described, a support, acircuit-controlling device mounted for rocking movement on the support,an expansible-collapsible corrugated vessel on said support and movabletoward and away Jtrom said circuit-controlling device, a lever fulcrumedon said support to one side of the axial line oi said vessel and havinga part engaged by said vessel, the upper end of said controlling meanshaving a range of movel l to the length of the lever throughout movementof said lever. Y

28. In a device of the character described,

ment, operating means responsive to pressure,

. a vlever for transmitting motion from said sure whereby the angle ooperating. means to said controlling means, spring means acting on saidlever at an acute angle, the angle of application of said spring meanson said lever being predetermined whereby the component of force exertedby said spring means on said lever prevents movement of said operatingmeans until the pressure of said operating means becomes equal to orslightly greater than the predetermined opposing componet of force ofsaid spring means, initial movement of said operating means decreasingthe angle of application of said spring means on said lever and theforce opposing said operating means whereby the pressure necessary toinitiate movement of said operating means will move said controllingmeans completely through its range of movement.

29. In a device of the character described, controlling means having arange of movement, a. sealed chamber containing a Huid and having aresilient Wall, a lever for transmitting motion from said wall to saidcontrolling means, said spring means acting at an acute angle .upon saidlever such that a component of force of said spring means opposes andholds said wall immovable until the fluid in said chamber exerts apredetermined pressure slightly in excess of the component of force ofsaid spring means exerted on said wall, said lever being moved byinitial movement of said wall at said predetermined presapplication ofsaid spring means on said lever is decreased, and

Athe opposing component of force of said spring means is overcome bysaid predetermined pressure to -cause said controlling means to be movedby said predetermined pressure completely through its range of movement.

In testimony whereof I have hereunto subscribed my name.

`LEWIS W. EGGLESTON.

